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EUG'ENTRIQ AND STRAP FORSTEAM ENGINES. 0. 275, 59. Patented Apr.10,1.883.

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. 1 II I I WITNESS ES: INVENTOR N. PETERS, Plmlo'hlhographen Washington, 7

UNITED STATES PATENT OFFICE.

NATHAN HUNT, OF SALEM, OHI O, ASSIGNOR OF ONE-HALF TO THE BUCK- EYE ENGINE COMPANY, OF SAME PLACE.

ECCENTRIC AND STRAP FOR STEAM-ENGINES.

SPECIFICATION formingpart of Letters Patent No. 275,659, dated April 10, 1883;

Application filed February 12, 1883. (No model.)

To all whom it may concern:

Be it known that I, NATHAN HUNT, ofSalem, in the county of Golumbiana and State of Ohio, have invented certain new and useful Improvements in Eccentrics and Straps for Stea mEngines, of which improvementsthe following is a specification.

The object of my invention is to perfect the operation of eccentrics and their straps, more particularly as employed for actuating the valves of steam-engines, by obviating the undue pressure and friction resultant upon disturbance of the normal alignment of the eccentric-rod; to which end my improvements consist in an eccentric having its wearing-surface in the form of a spherical zone; also, in

an eccentric-strap having its internal surface spherically recessed or bored out; also, in the combination of an eccentric and an eccentric- 2o strap the surfaces of contact of which are at all points correspondingly spherical.

The improvements claimed are hereinafter more fully set forth. 7

' In the accompanying drawings, Figure 1 is 2 a side view, in elevation, of an eccentric and eccentric-strap embodying my invention Fig. 2, ahorizontal central section through the same, and Fig. 3 a view in elevation of the smaller section of the eccentric as seen from the t p.

My improvements are herein illustrated as applied to a split or divided eccentric, A,'composed of two sections, 1 2, but, as will be ob- ..vious, are equally applicable to eccentrics formed in a single piece. The strap B is, as usual, composed of two sections, 3 4, connected by bolts 11 and nuts b, and the eccentricrod 0 is connected to the section 3 by screwthreads and a nut, c. As heretofore constructed, the wearing-surface of the eccen trio and the corresponding surface of the strap have been made either cylindrical or with a" curvature the center of which does not coincide with the geometrical axis of the eccentric. In either of such cases proper wearing-contact is possi- 4 5 ble only during the perfect normal alignment of the eccentric-rod, and any disturbance of or variation therefrom tends to concentrate the pressure and friction due to the performance of the functions of the parts upon limited portions of the wearing-surfaces, thereby causing heating and unsatisfactory performance in other respects.

In the practice of my invention 1 form the wearing-surface a of the eccentric as a spherical zone by turning itto a radius of peripheral curvature, w, the center of which coincides with the geometrical axis 3/ y of the eccentric, and I recess or bore out the strap B, so that its wearing-surface b shall present throughout a corresponding spherical curvature. The width of the wearing-surface of the eccentric is such as to admit of clearance between the eccentricstrap and the flange or collar a of the eccentric, thereby permitting such movement of the strap upon the eccentric about the center of the curvature of the wearing-surfaces as may be occasioned by variations of the cocentric-rod G from its true alignment, in any and all of which variations the frictional rela tion of the wearing-surfaces one to the other will remain undisturbed, and cramping, binding, or unequal friction at different points is efi'ectuallyprevented.

Disclaiming broadly an eccentric or strap having a curved wearing-surface, I claim as my invention and desire to secure by Letters Patent- 1. An eccentric having its wearing-surface in the form of a spherical zonethat is to say, of a peripheral curvature the center of which coincides with the geometrical axis of the cocentric.

2. An eccentric-strap which is internally recessed or bored out to a curvature the center of which coincides with its geometrical axis.

3. The combination, substantially as set forth, of an eccentric and an eccentric-strap the \i-earing-surfaces of which are at all points.

of corresponding spherical curvature.

NATHAN HUNT.

Witnesses PETER AMBLER,

H. P. GAMBLE. 

